1. Field of the Invention
The present invention relates to a service mode of a video cassette tape recorder, and more particularly to a method and an apparatus for interactively changing an EEPROM data in a video cassette tape recorder following instructional pictures on a television screen by using a remote controller during a test or a repair thereof without any special instruments.
2. Description of the Prior Art
A video cassette tape recorder is designed and manufactured with a spec adequate to a received television broadcasting type such as an NTSC, a PAL and a SCECAM. Accordingly, manufacturers of the video cassette tape recorder adopt a scheme for improving a productivity by a unification and a standardization of components thereof in order to produce various productions adequate to various broadcasting type in one processing line.
Following the technical trends as mentioned above, the video cassette tape recorder adopts an integration of circuit components and a microcomputer control method and adopts a serial transmission method by which each circuit block and the microcomputer transfer a data therebetween. By adopting the serial transmission method, a circuit characteristic of a circuit block is easily changed according to various options. An option spec of each circuit block is standardized as a table so that an option data adequate to a set is set into an EEPROM with reference to the standardized table in producing and assembling levels.
U.S. Pat. No. 5,506,892 discloses a technique for rewriting the EEPROM data of the video cassette tape recorder by Local Application Control bus System (LANC).
As described above, since the conventional EEPROM data can be changed in a state where a special instrument such as a computer is connected to the set, the EEPROM data cannot be changed where there is no special instrument. So, there are obstacles in carrying out an operation at a laboratory, a test of a processing line and an after service.
More particularly, when the worker goes to a consumer's home to service the product, and if an error is detected, the worker cannot change circuit parameters at the place and must carry the set to an after-service center. So, the after service cannot be promptly carried out, and also takes an increased after service charge therewith. Also, a special instrument such as a computer must be used, which requires a trained technician.